Biomechanical comparison of three fixation techniques for unstable thoracolumbar burst fractures

2008 ◽  
Vol 8 (4) ◽  
pp. 341-346 ◽  
Author(s):  
Frank L. Acosta ◽  
Jenni M. Buckley ◽  
Zheng Xu ◽  
Jeffrey C. Lotz ◽  
Christopher P. Ames
Keyword(s):  
Burst Fracture ◽  
Axial Rotation ◽  
Short Segment ◽  
Thoracolumbar Burst Fractures ◽  
Spinal Reconstruction ◽  
Burst Fractures ◽  
Flexion Extension ◽  
Circumferential Fusion ◽  
Fixation Techniques ◽  
Biomechanical Comparison

Object Increased structural stability is considered sufficient justification for higher-risk surgical procedures, such as circumferential fixation after severe spinal destabilization. However, there is little biomechanical evidence to support such claims, particularly after traumatic lumbar burst fracture. The authors sought out to compare the biomechanical performance of the following 3 fixation strategies for spinal reconstruction after decompression for an unstable thoracolumbar burst fracture: 1) short-segment anterolateral fixation; 2) circumferential fixation; and 3) extended anterolateral fixation. Methods Thoracolumbar spines (T10–L4) from 7 donors (mean age at death 64 ± 6 years; 1 female and 6 males) were tested in pure moment loading in flexion–extension, lateral bending, and axial rotation. Thoracolumbar burst fractures were surgically induced at L-1, and testing was repeated sequentially for each of the following fixation techniques: short-segment anterolateral, circumferential, and extended anterolateral. Primary and coupled 3D motions were measured across the instrumented site (T12–L2) and compared across treatment groups. Results Circumferential and extended anterolateral fixations were statistically equivalent for primary and off-axis range-of-motions in all loading directions, and short-segment anterolateral fixation offered significantly less rigidity than the other 2 methods. Conclusions The results of this study strongly suggest that extended anterolateral fixation is biomechanically comparable to circumferential fusion in the treatment of unstable thoracolumbar burst fractures with posterior column and posterior ligamentous injury. In cases in which an anterior procedure may be favored for load sharing or canal decompression, extension of the anterior instrumentation and fusion one level above and below the unstable segment can result in near equivalent stability to a 2-stage circumferential procedure.

A comparison of single and incremental impact approaches for producing experimental thoracolumbar burst fractures

2007 ◽  
Vol 7 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Xiang-Yang Wang ◽  
Li-Yang Dai ◽  
Hua-Zi Xu ◽  
Yong-Long Chi
Keyword(s):  
Burst Fracture ◽  
Axial Rotation ◽  
Similar Degree ◽  
Thoracolumbar Burst Fractures ◽  
Single Impact ◽  
Burst Fractures ◽  
Flexion Extension ◽  
The Impact ◽  
Flexibility Parameters

Object. Experimental burst fracture models are often developed by using either single or incremental impacts. In both protocols, the weight-drop technique produces the impact. However, to the authors' knowledge in no study have researchers attempted to compare the equivalence of the spine burst fracture produced using the different impact protocols. This study was performed to investigate whether the single and incremental trauma approaches produce equivalent degrees of severity in thoracolumbar burst fractures. Methods. Twenty bovine thoracolumbar spines comprising three vertebrae were divided evenly into the single impact and incremental impact groups. The specimens in the incremental impact group were subjected to three axial compressive impacts of increasing energy (78.4, 107.8, and 137.2 J), whereas specimens in the other group were subjected to a single impact (137.2 J). Before and after the final trauma, multidirectional flexibility of each specimen was measured under flexion/extension, right/left lateral bending, and right/left axial rotation, thus quantifying the instability of the fracture. The flexibility parameters were then compared between the two groups. Results. A significant increase in flexibility parameters was found after the final trauma in both groups, indicating the instability of the spine (p < 0.01). No significant differences in flexibility parameters were observed in either intact status or injured status between the two groups (p > 0.05). Conclusions. In this study the authors have confirmed that the single and incremental impact protocols produced a similar degree of severity in producing an in vitro bovine burst fracture. The results of this study support the use of the incremental impact protocol in future experimental biomechanical studies.

scholarly journals Biomechanical comparison of short-segment posterior fixation including the fractured level and circumferential fixation for unstable burst fractures of the lumbar spine in a calf spine model

2016 ◽  
Vol 25 (5) ◽  
pp. 602-609 ◽  
Author(s):  
Azad Sait ◽  
Nadipi Reddy Prabhav ◽  
Vijay Sekharappa ◽  
Reshma Rajan ◽  
N. Arunai Nambi Raj ◽  
...  
Keyword(s):  
Burst Fracture ◽  
Thoracolumbar Spine ◽  
Axial Rotation ◽  
Posterior Fixation ◽  
Lateral Flexion ◽  
Short Segment ◽  
Burst Fractures ◽  
Flexion Extension ◽  
Group A ◽  
Group B

OBJECTIVE There has been a transition from long- to short-segment instrumentation for unstable burst fractures to preserve motion segments. Circumferential fixation allows a stable short-segment construct, but the associated morbidity and complications are high. Posterior short-segment fixation spanning one level above and below the fractured vertebra has led to clinical failures. Augmentation of this method by including the fractured level in the posterior instrumentation has given promising clinical results. The purpose of this study is to compare the biomechanical stability of short-segment posterior fixation including the fractured level (SSPI) to circumferential fixation in thoracolumbar burst fractures. METHODS An unstable burst fracture was created in 10 fresh-frozen bovine thoracolumbar spine specimens, which were grouped into a Group A and a Group B. Group A specimens were instrumented with SSPI and Group B with circumferential fixation. Biomechanical characteristics including range of motion (ROM) and load-displacement curves were recorded for the intact and instrumented specimens using Universal Testing Device and stereophotogrammetry. RESULTS In Group A, ROM in flexion, extension, lateral flexion, and axial rotation was reduced by 46.9%, 52%, 49.3%, and 45.5%, respectively, compared with 58.1%, 46.5%, 66.6%, and 32.6% in Group B. Stiffness of the construct was increased by 77.8%, 59.8%, 67.8%, and 258.9% in flexion, extension, lateral flexion, and axial rotation, respectively, in Group A compared with 80.6%, 56.1%, 82.6%, and 121.2% in Group B; no statistical difference between the two groups was observed. CONCLUSIONS SSPI has comparable stiffness to that of circumferential fixation.

scholarly journals Biomechanical study of a semi-rigid stabilization system combined with transpedicular intracorporeal bone grafting for thoracolumbar burst fractures

2020 ◽  
Author(s):  
xiaoyong zheng ◽  
qingwen yu ◽  
zhi zhang
Keyword(s):  
Bone Grafting ◽  
Burst Fracture ◽  
Axial Rotation ◽  
Biomechanical Study ◽  
Stabilization System ◽  
Thoracolumbar Burst Fracture ◽  
Lateral Bending ◽  
Thoracolumbar Burst Fractures ◽  
Burst Fractures ◽  
Flexion Extension

Abstract Background: For fresh thoracolumbar burst fracture, a new method which can not only promote the fracture healing, but also retain the movement segment, and restore the spinal movement function to the maximum extent is needed. The purpose of this study is to determine the performance of stabilization of a semi-rigid stabilization system combined with transpedicular intracorporeal bone grafting for thoracolumbar burst fractures.Methods Six thoracolumbar cadaver spines were used for testing. A controlled L2 burst fracture was created. The L1-3 motions were determined.Results In extension, flexion and lateral bending, the semi-rigid fixator stabilized the segment to a range of motion(ROM) and neutral zone(NZ) below the magnitude of the intact spine, but showed increased ROM and NZ of axial rotation (P < 0.05) compared with the intact spine.Conclusions Restoration of stability with the semi-rigid dynamic system combined with transpedicular intracorporeal bone grafting is possible in flexion, extension, right and left lateral bending for thoracolumbar burst fracture but for axial rotation.

Restabilization of the Occipitocervical Junction After a Complete Unilateral Condylectomy: A Biomechanical Comparison of Unilateral and Bilateral Fixation Techniques

2019 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Ilyas M Eli ◽  
Michael Karsy ◽  
Darrel S Brodke ◽  
Kent N Bachus ◽  
William T Couldwell ◽  
...  
Keyword(s):  
Biomechanical Testing ◽  
Axial Rotation ◽  
Neurological Injury ◽  
Occipital Condyle ◽  
Posterior Fixation ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Fixation Techniques ◽  
The Difference ◽  
Biomechanical Comparison

Abstract BACKGROUND Occipitocervical instability may result from transcondylar resection of the occipital condyle. Initially, patients may be able to maintain a neutral alignment but severe occipitoatlantal subluxation may subsequently occur, with cranial settling, spinal cord kinking, and neurological injury. OBJECTIVE To evaluate the ability of posterior fixation constructs to prevent progression to severe deformity after radical unilateral condylectomy. METHODS Eight human cadaveric specimens (Oc-C2) underwent biomechanical testing to compare stiffness under physiological loads (1.5 N m). A complete unilateral condylectomy was performed to destabilize one Oc-C1 joint, and the contralateral joint was left intact. Unilateral Oc-C1 or Oc-C2 constructs on the resected side and bilateral Oc-C1 or Oc-C2 constructs were tested. RESULTS The bilateral Oc-C2 construct provided the greatest stiffness, but the difference was only statistically significant in certain planes of motion. The unilateral constructs had similar stiffness in lateral bending, but the unilateral Oc-C1 construct was less stiff in axial rotation and flexion-extension than the unilateral Oc-C2 construct. The bilateral Oc-C2 construct was stiffer than the unilateral Oc-C2 construct in axial rotation and lateral bending, but there was no difference between these constructs in flexion-extension. CONCLUSION Patients who undergo a complete unilateral condylectomy require close surveillance for occipitocervical instability. A bilateral Oc-C2 construct provides suitable biomechanical strength, which is superior to other constructs. A unilateral construct decreases abnormal motion but lacks the stiffness of a bilateral construct. However, given that most patients undergo a partial condylectomy and only a small proportion of patients develop instability, there may be scenarios in which a unilateral construct may be appropriate, such as for temporary internal stabilization.

Biomechanical Evaluation of Short-Segment Posterior Instrumentation With Crosslinks in an Unstable Human Burst Fracture Model

2009 ◽  
Author(s):  
George M. Wahba ◽  
Nitin N. Bhatia ◽  
Thay Q. Lee
Keyword(s):  
Clinical Studies ◽  
Posterior Instrumentation ◽  
Burst Fracture ◽  
Fracture Model ◽  
Short Segment ◽  
Thoracolumbar Burst Fractures ◽  
Burst Fractures ◽  
Sufficient Stability ◽  
Biomechanical Evaluation ◽  
Serious Injuries

Unstable thoracolumbar burst fractures are serious injuries and their management remains controversial. Some authors advocate the use of short-segment posterior instrumentation (SSPI) for certain burst fractures which offers several benefits including preservation of motion segments; however, clinical studies have shown mixed results. Whether crosslinks contribute sufficient stability to this construct has not been determined, therefore the objective of this study was to evaluate the biomechanical characteristics of short-segment posterior instrumentation, with and without crosslinks, in an unstable human burst fracture model.

Biomechanical Comparison of Four C1 to C2 Rigid Fixative Techniques: Anterior Transarticular, Posterior Transarticular, C1 to C2 Pedicle, and C1 to C2 Intralaminar Screws

Neurosurgery ◽  
2006 ◽  
Vol 58 (3) ◽  
pp. 516-521 ◽  
Author(s):  
Samir B. Lapsiwala ◽  
Paul A. Anderson ◽  
Ashish Oza ◽  
Daniel K. Resnick
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Axial Rotation ◽  
Lateral Bending ◽  
Transarticular Screw ◽  
Transarticular Screw Fixation ◽  
Flexion Extension ◽  
Fixation Techniques ◽  
Biomechanical Comparison ◽  
Cable Fixation

Abstract OBJECTIVE: We performed a biomechanical comparison of several C1 to C2 fixation techniques including crossed laminar (intralaminar) screw fixation, anterior C1 to C2 transarticular screw fixation, C1 to 2 pedicle screw fixation, and posterior C1 to C2 transarticular screw fixation. METHODS: Eight cadaveric cervical spines were tested intact and after dens fracture. Four different C1 to C2 screw fixation techniques were tested. Posterior transarticular and pedicle screw constructs were tested twice, once with supplemental sublaminar cables and once without cables. The specimens were tested in three modes of loading: flexion-extension, lateral bending, and axial rotation. All tests were performed in load and torque control. Pure bending moments of 2 nm were applied in flexion-extension and lateral bending, whereas a 1 nm moment was applied in axial rotation. Linear displacements were recorded from extensometers rigidly affixed to the C1 and C2 vertebrae. Linear displacements were reduced to angular displacements using trigonometry. RESULTS: Adding cable fixation results in a stiffer construct for posterior transarticular screws. The addition of cables did not affect the stiffness of C1 to C2 pedicle screw constructs. There were no significant differences in stiffness between anterior and posterior transarticular screw techniques, unless cable fixation was added to the posterior construct. All three posterior screw constructs with supplemental cable fixation provide equal stiffness with regard to flexion-extension and axial rotation. C1 lateral mass-C2 intralaminar screw fixation restored resistance to lateral bending but not to the same degree as the other screw fixation techniques. CONCLUSION: All four screw fixation techniques limit motion at the C1 to 2 articulation. The addition of cable fixation improves resistance to flexion and extension for posterior transarticular screw fixation.

scholarly journals Spinal Reconstruction Techniques for Traumatic Spinal Injuries: A Systematic Review of Biomechanical Studies

2018 ◽  
Vol 9 (3) ◽  
pp. 338-347 ◽  
Author(s):  
Andrei F. Joaquim ◽  
Joseph P. Maslak ◽  
Alpesh A. Patel
Keyword(s):  
Systematic Review ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Burst Fracture ◽  
Posterior Fixation ◽  
Injury Patterns ◽  
Spinal Reconstruction ◽  
Burst Fractures ◽  
Circumferential Fusion ◽  
Fracture Level

Study Design: Systematic literature review. Objectives: Many studies have provided evidence that short-segment posterior fixation (SSPF—1 level above and 1 below) with screws at the fracture level (SFL) are enough to achieve stability in some injury patterns, such as burst fractures, avoiding the need for circumferential reconstruction and long-segment instrumented fusion (LSIF—at least 2 levels above and 2 below). Given the potential benefits of avoiding unnecessary fusion in mobile healthy spinal segments, we performed a systematic review of biomechanical studies comparing different spinal reconstruction techniques for fractures of the thoracolumbar spine. Methods: A systematic literature review was performed in the PubMed and OVID databases of biomechanical studies comparing biomechanical differences between techniques of spine reconstructions. Results: Eight studies were included and evaluated. Five of 6 studies reported stiffness improvement with SSPF and SFL, even comparable to circumferential fusion for a burst fracture. Two studies reported that LSPF has higher stiffness and restricts range of motion better than SSPF, but inclusion of screws in the fracture level is similar to LSPF (1 study). Finally, although SSPF is less stiff than anterior reconstruction, adding a SFL in SSPF results in similar stiffness than circumferential fusion for unstable burst fractures. Conclusions: Biomechanical studies analyzed generally suggested that SFL in SSPF may improve construction stiffness, and can even be compared with long-segment fixation or circumferential reconstruction in some scenarios. This construct option may be used to enhance stiffness in selected injury patterns, avoiding the needs of an additional anterior approach.

Biomechanical Comparison of Short-Segment Fixation Methods to Treat Thoracolumbar Burst Fractures

2012 ◽  
Vol 12 (9) ◽  
pp. S132-S133 ◽  
Author(s):  
Jacob M. Buchowski ◽  
Hani H. Mhaidli ◽  
Julie L. Reigrut ◽  
John A. Schmidt
Keyword(s):  
Short Segment ◽  
Thoracolumbar Burst Fractures ◽  
Fixation Methods ◽  
Burst Fractures ◽  
Short Segment Fixation ◽  
Biomechanical Comparison

scholarly journals Biomechanical Evaluation of Unilateral Versus Bilateral C1 Lateral Mass-C2 Intralaminar Fixation

2017 ◽  
Vol 7 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Nitin Bhatia ◽  
Asheen Rama ◽  
Brandon Sievers ◽  
Ryan Quigley ◽  
Michelle H. McGarry ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Axial Rotation ◽  
Biomechanical Properties ◽  
Lateral Mass ◽  
Intact State ◽  
Flexion Extension ◽  
Fixation Techniques ◽  
Rotation Stiffness ◽  
Biomechanical Evaluation ◽  
C2 Fixation

Study Design: Biomechanical, cadaveric study. Objectives: To compare the relative stiffness of unilateral C1 lateral mass-C2 intralaminar fixation to intact specimens and bilateral C1 lateral mass-C2 intralaminar constructs. Methods: The biomechanical integrity of a unilateral C1 lateral mass-C2 intralaminar screw construct was compared to intact specimens and bilateral C1 lateral mass-C2 intralaminar screw constructs. Five human cadaveric specimens were used. Range of motion and stiffness were tested to determine the stiffness of the constructs. Results: Unilateral fixation significantly decreased flexion/extension range of motion compared to intact ( P < .001) but did not significantly affect axial rotation ( P = .3) or bending range of motion ( P = .3). There was a significant decrease in stiffness in extension for both unilateral and bilateral fixation techniques compared to intact ( P = .04 and P = .03, respectively). There was also a significant decrease in stiffness for ipsilateral rotation for the unilateral construct compared to intact ( P = .007) whereas the bilateral construct significantly increased ipsilateral rotation stiffness compared to both intact and unilateral fixation ( P < .001). Conclusion: Bilateral constructs did show improved biomechanical properties compared to the unilateral constructs. However, unilateral C1-C2 fixation using a C1 lateral mass and C2 intralaminar screw-rod construct decreased range of motion and improved stiffness compared to the intact state with the exception of extension and ipsilateral rotation. Hence, a unilateral construct may be acceptable in clinical situations in which bilateral fixation is not possible, but an external orthosis may be necessary to achieve a fusion.

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